Formation of epichlorohydrin, a known rodent carcinogen, following oral administration of 1,3-dichloro-2-propanol in rats

Targeted release of soybean peptide from CMC/PVA hydrogels in simulated intestinal fluid and their pharmacokinetics

Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) hydrogels loaded with soybean peptide (SPE) were fabricated via a freeze-thaw method. These hydrogels conquer barriers in simulated gastric fluid (SGF), and then release SPE in simulated intestinal fluid (SIF). The results of in vitro SPE release from these hydrogels showed that in SGF only a little of the SPE released, but in SIF the SPE was completely released. The released SPE had scavenging rates for DPPH and ABTS free radicals of 41.68 and 31.43 %. The pharmacokinetic model of SPE release from the hydrogels in SIF was studied. When the hydrogels are moved from SGF to SIF, the sorption of the shrinkage hydrogel network is entirely controlled by stress-induced relaxations. There are swollen and shrunken regions during SPE release. For SPE release into the SIF, SPE has to be freed from the weak bonds in the swollen regions by changes in the conformation of CMC and PVA. The release rate of SPE was found to be governed by the diffusion and swelling rate of the shrinkage hydrogel network. The Korsmeyer-Peppas equation diffusion exponents (n) for SPE release from the hydrogels are >2.063, indicating a super case II transport. These data demonstrate CMC/PVA hydrogels have potential applications in oral peptide delivery.

Surface-modified biopolymers for removing mixtures of per- and polyfluoroalkyl substances from water: Screening and removal mechanisms

Green, renewable, and sustainable materials are needed for removing per- and polyfluoroalkyl substances (PFASs) in water. Herein, we synthesized and tested alginate (ALG) and chitosan (CTN) based and polyethyleneimine (PEI) functionalized fibers/aerogels for the adsorption of mixtures of 12 PFASs (9 short- and long-chain PFAAs, GenX, and 2 precursors) from water at an initial concentration of 10 μg/L each. Out of 11 biosorbents, ALGPEI-3 and GTH CTNPEI aerogels had the best sorption performance. Through detailed characterization of the sorbents before and after PFASs sorption, it was revealed that hydrophobic interaction was the dominant mechanism controlling PFASs sorption while electrostatic interactions played a minor role. As a result, both aerogels had fast and superior sorption of relatively hydrophobic PFASs from pH 2 to 10. Even at extreme pH conditions, the aerogels retained their shape perfectly. Based upon the isotherms, the maximum adsorption capacity of ALGPEI-3 and GTH-CTNPEI aerogels towards total PFASs removal was 3045 and 12,133 mg/g, respectively. Although the sorption performance of the GTH-CTNPEI aerogel toward short chain PFAS was less than satisfactory and varied between 70 and 90% in 24 h, it may find its use in removing relatively hydrophobic PFAS at high concentrations in complex and extreme environments.

Contribution of the Surface Treatment of Nanofibrillated Cellulose on the Properties of Bio-Based Epoxy Nanocomposites Intended for Flexible Electronics

The growing interest in materials derived from biomass has generated a multitude of solutions for the development of new sustainable materials with low environmental impact. We report here, for the first time, a strategy to obtain bio-based nanocomposites from epoxidized linseed oil (ELO), itaconic acid (IA), and surface-treated nanofibrillated cellulose (NC). The effect of nanofibrillated cellulose functionalized with silane (NC/S) and then grafted with methacrylic acid (NC/SM) on the properties of the resulted bio-based epoxy systems was thoroughly investigated. The differential scanning calorimetry (DSC) results showed that the addition of NCs did not influence the curing process and had a slight impact on the maximum peak temperature. Moreover, the NCs improved the onset degradation temperature of the epoxy-based nanocomposites by more than 30 °C, regardless of their treatment. The most important effect on the mechanical properties of bio-based epoxy nanocomposites, i.e., an increase in the storage modulus by more than 60% at room temperature was observed in the case of NC/SM addition. Therefore, NC's treatment with silane and methacrylic acid improved the epoxy-nanofiber interface and led to a very good dispersion of the NC/SM in the epoxy network, as observed by the SEM investigation. The dielectric results proved the suitability of the obtained bio-based epoxy/NCs materials as substitutes for petroleum-based thermosets in the fabrication of flexible electronic devices.

Improved solid-phase microextraction extraction procedure to detect trace-level epichlorohydrin in municipal water systems by HS-SPME-GC/MS

Epichlorohydrin (ECH) is toxic to humans via multiple routes and is a potential carcinogen. The accurate measurement of ECH at trace level (<0.1 μg/L) is still an obstacle hindering the monitoring and regulation of municipal water systems. In this study, an improved headspace solid-phase microextraction (HS-SPME) procedure is developed and optimized to extract and enrich ECH with high sensitivity, accuracy, and precision. A total 17.4-time enhancement in extraction efficiency is achieved compared with the default condition. Specifically, the AC/PDMS/DVB fiber offered a 4.4-time enhancement comparing with the PDMS/DVB fiber. The effects of different mineral salts in SPME were studied and it was found that an addition of 3 g Na₂SO₄ in the SPME head achieved an additional 3.3-time increase. The pattern how sodium sulfate enhanced ECH extraction by salting out is discussed. The optimization of extraction conditions (pH = 7, 35°C, and 20 min extraction duration) brought another 1.2 times further. Combined with gas chromatography with mass spectrometry, the optimized method exhibits curve linearity in the range of 0.02–1.00 μg/L with an R² of 0.998. The limit of detection, precision, and accuracy of the method are 0.006 μg/L, 2.6%–5.3%, and −3.5% to −2.0%, respectively. The recovery of ECH spiking in tap water and surface water was investigated, with recovery rates of 88.0%–116% and 72.5%–108%, respectively. Adhering to the requirements of existing water quality regulations, our method shows a high potential to be applied in drinking water quality monitoring and water treatment process assessment.

The common indoor air pollutant α-pinene is metabolized to a genotoxic metabolite α-pinene oxide

1. α-Pinene caused a concentration-responsive increase in bladder hyperplasia and decrease in sperm counts in rodents following inhalation exposure. Additionally, it formed a prospective reactive metabolite, α-pinene oxide.2. To provide human relevant context for data generated in animal models and explore potential mechanism, we undertook studies to investigate the metabolism of α-pinene to α-pinene oxide and mutagenicity of α-pinene and α-pinene oxide.3. α-Pinene oxide was formed in rat and human microsomes and hepatocytes with some species differences. Based on area under the concentration versus time curves, the formation of α-pinene oxide was up to 4-fold higher in rats than in humans.4. While rat microsomes cleared α-pinene oxide faster than human microsomes, the clearance of α-pinene oxide in hepatocytes was similar between species.5. α-Pinene was not mutagenic with or without induced rat liver S9 in Salmonella typhimurium or Escherichia coli when tested up to 10,000 μg/plate while α-pinene oxide was mutagenic at ≥25 μg/plate.6. α-Pinene was metabolized to α-pinene oxide under the conditions of the bacterial mutation assay although the concentration was approximately 3-fold lower than the lowest α-pinene oxide concentration that was positive in the assay, potentially explaining the lack of mutagenicity observed with α-pinene.

In vivo mutagenicity and tumor-promoting activity of 1,3-dichloro-2-propanol in the liver and kidneys of gpt delta rats

1,3-Dichloro-2-propanol (1,3-DCP), a food contaminant, exerts carcinogenic effects in multiple organs, including the liver and kidneys, in rats. However, the underlying mechanisms of 1,3-DCP-induced carcinogenesis remain unclear. Here, the in vivo mutagenicity and tumor-promoting activity of 1,3-DCP in the liver and kidneys were evaluated using medium-term gpt delta rat models previously established in our laboratory (GPG and GNP models). Six-week-old male F344 gpt delta rats were treated with 0 or 50 mg/kg body weight/day 1,3-DCP by gavage for 4 weeks. After 2 weeks of cessation, partial hepatectomy or unilateral nephrectomy was performed to collect samples for in vivo mutation assays, followed by single administration of diethylnitrosamine (DEN) for tumor initiation. One week after DEN injection, 1,3-DCP treatment was resumed, and tumor-promoting activity was evaluated in the residual liver or kidneys by histopathological analysis of preneoplastic lesions. gpt mutant frequencies increased in excised liver and kidney tissues following 1,3-DCP treatment. 1,3-DCP did not affect the development of glutathione S-transferase placental form-positive foci in residual liver tissues, but enhanced atypical tubule hyperplasia in residual kidney tissues. Detailed histopathological analyses revealed glomerular injury and increased cell proliferation of renal tubular cells in residual kidney tissues of rats treated with 1,3-DCP. These results suggested possible involvement of genotoxic mechanisms in 1,3-DCP-induced carcinogenesis in the liver and kidneys. In addition, we found that 1,3-DCP exhibited limited tumor-promoting activity in the liver, but enhanced clonal expansion in renal carcinogenesis via proliferation of renal tubular cells following glomerular injury.

In vivo epiclorohidrine toxicity: cytogenetic, biochemical, physiological, and anatomical evidences

In this study, the toxic effects of epiclorohidrine (ECh) were investigated in vivo by Allium test. The toxic effects have been investigated in terms of physiological, cytogenetic, anatomical, and biochemical aspects. The changes in germination percentage, weight gain, and root length were investigated as physiological parameter; micronucleus (MN), mitotic index (MI), and chromosomal abnormality (CA) frequencies were as cytogenetic parameter. Oxidative stress indicators such as superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were analyzed for biochemical changes and also damages in root tip cells were evaluated as anatomical parameter. It was determined that germination percentage, weight gain, root length, and MI decreased; MN and CA frequencies were increased with the increase of ECh treatment dose. ECh treatment caused significant increase in SOD and CAT enzyme activities and MDA levels and these results indicated a stress formation. A variety of anatomical changes and damages were observed in the root tip cells induced by ECh. In conclusion, the toxic effects of ECh on A. cepa which is a model of eucaryotic cell were investigated in a multi-directional way and serious toxic effects of ECh treatment were determined.